This. I wonder why so many seem so eager to engage in the fantasy that Intel (and AMD) are planning to jump ship to ARM or RISC-V.
Yes, ISA's matter, to a point. And yes, ARM64 and RISC-V are much closer to 'best practice' ISA design than x86 with all its legacy baggage. But enough better to make AMD&Intel throw away the x86 market and their position in that as explained in the parent comment? No effing way.
Intel has tried to move away from x86 three times already. They only stuck with it in the early 2000s because AMD64 forced their hand.
This chip shows why Intel would like RISC-V. The core ISA is RISC-V, but every other piece of the chip is proprietary and patented Intel stuff. They are far ahead of almost everyone in these areas, so they don't have much to fear in their current markets from the ISA itself.
Few companies have the ability, desire, or connections to spend billions designing a next-gen chip. China has thoroughly proved this. They have designed for x86, Alpha, MIPS, ARM, RISC-V, etc, but none of their designs were particularly good. For example, they recently released their Phytium D2000 chip. It was basically a clone of A72 with improvements, but chips and cheese analysis[0] showed that the supposed improvements actually resulted in a worse design.
If designing a good high-performance chip was down to just ISA, then everyone would be doing it.
Meanwhile, x86 patents for SSE2 and before have expired (with SSE3 expiring in 2023-4). Analysis of real-world code shows that only a couple percent use something beyond SSE3 and pretty much all of that has fallbacks for SSE2. There's already not much left to keep companies from designing x86-compatible chips (Apple's Rosetta x86 compatibility tracks this expiration exactly).
At the same time, x86 is incapable of competing in MCU and DSP markets and Intel's phone offerings were flatly rejected and only competitive when they had the huge advantage of being a couple fabrication nodes ahead of their competitors. Intel paid billions trying to make it happen, but never had many sales outside of the lemonade they made in the embedded market.
Intel and AMD would far rather have a non-proprietary solution like RISC-V win than a proprietary one like ARM.
I wouldn't say "move away", I would say "augment their product line".
What are the three? I can only think of two: IA64 and i960, but those weren't departures.
I worked on Itanium (and McKinely, and Madison). They were never intended for desktops. (In fact, back then there was still this notion of Desktop and Workstation, which is essentially dead today.)
The i960 was a fantastic CPU and I only know the wikipedia version of what happened to it, since it was before my time (well, they were producing it when I worked there, but I was ignorant of the climate). However, it was never a "move away from x86" product, it had great # of embedded customers. Again, never for desktops.
I think it's fair to say though it was intended to be a move away from the main PC microprocessor line (which you can argue traced a path through 8080 to 8086 and beyond ) and ultimately replace it at the high end - so in spirit similar to Itanium even if not an 'x86 replacement'.
x86 traces it's DNA all the way back to the 8008 which led to the extended 8080 which led to the backward compatible 8085 then 8086 and the x86 architecture.
8008 was almost a full decade before the launch of the iAPX 432.
The roots of x86 were in one of the first major ISAs ever created (and something like the 2nd or 3rd microprocessor architecture) which is pretty remarkable when you think about it.
I think the real reason is they're thinking about opening their foundry to external customers in a meaningful way.
A modern foundry is expected to have a suite of hard IP blocks to drop on a design to cover PPA sensitive blocks like CPUs someone would want, and blocks with analog bits like PHYs. Best way to ameliorate people's concerns is to have shipped a chip that runs with those blocks.
> Intel's phone offerings were flatly rejected and only competitive when they had the huge advantage of being a couple fabrication nodes ahead of their competitors.
I think there was a good amount of ecosystem issues there. Android x86 phones shipped and were ok, but too many apps shipped native code without an x86 flavor; I don't remember if Google had per-arch builds on Play Store yet, but those also cause issues because people pull those builds and host them on apkg sites, then users have problems when installing them on wrong arch phones.
Intel canceled the atom for phones lines days before Microsoft demoed Continuum, which would have been an obvious outlet for an x86 phone. Of course, Microsoft threw in the towel on WM10 before launch too, so maybe Intel wasn't willing to stick it out because they saw Microsoft was going to mess it up. In an alternate reality, the Lumia 950 would be a phone in your pocket and an x86 desktop running real apps on your desk, instead of stuck running app store apps and (pre-chromium) Edge only.
The important x86 patents are all expiring. Nothing would prevent a third party from recreating AVX using different instruction designs that would avoid those patents too.
The non-commodity stuff is all the interconnects, memory controllers, caches, etc. Having access to the Athlon XP or Pentium 4 cache, interconnect, or MC designs simply doesn't matter. Intel has these bits locked down already.
As the ISA is commodity, the only parts that matter are efficiency, compatibility, extensibility, and cost.
RISC-V allows them to penetrate new markets where x86 either can't compete or people don't believe it could compete because it is much more efficient at the low end. On the high-end, simplifying stuff in one area means you have the ability to increase the complexity and performance somewhere else.
On the compatibility front, Apple has already forced their hand by being compatible enough to offer a path to ARM.
x86 is not so extensible at this point. Lots of the best instruction encodings are wasted on stuff like BCD and even x86_64 has lots of legacy and extensibility issues. RISC-V not only solves this problem, but Intel is big enough to exert a lot of pressure on future standards.
Cost is a problem that isn't to be underestimated. ARM charges 1-3% per chip. That's something like 8-10% of gross margins. RISC-V means Intel can get a new ISA that is already being picked up by everyone (rather than spending billions on forcing a new one only to fail as they've already done).
In short, there are a lot of advantages and very few downsides to Intel making the switch.
Not that I expect it to happen any time soon, but Intel and AMD are proving with every release they have nothing for energy efficient machines. M1 battery is almost always the first thing people mention. And as M2 gets released, more people will get used/cheaper M1s. Companies release more aarch64-compatible software and even games every day.
At some point the x86 companies will either have to respond or see more and more people migrate to either Apple or other arm laptops (serious alternatives are not here yet, but a few producers are starting to experiment)
> AMD are proving with every release they have nothing for energy efficient machines
Every release AMD has done lately has two sides: side A is for the same compute as previously, you use less watts; side B is for the same watts, you get more compute; the third side is often oh yeah, you can pump a lot more watts (Zen4 almost doubled TDP on the high end parts, to compete with Intel's raised TDPs).
If you want an energy efficient AMD machine, you just have to limit the wattage. It may or may not get all the way to M1/M2 level of efficiency, but it's decent. Of course, lots of people are going to prefer performance, and it makes sense for AMD to allow that if system design can handle the power supply and cooling requirements. Apple gets to design their CPUs around an assumption that clock speed won't need to scale because cooling will not be sufficient for astronomical clocks, but Intel and AMD are in a competitive market where clock speed sells chips, so everything needs to scale. Arm's more relaxed memory model helps Apple as well.
Apple has been busy making their chips more efficient, while simultaneously putting beefier coolers & PSUs in their latest design. I believe Apple have enough leverage to raise their clock speed.
I forgot to add that there is the risk of 'Osborning'[1] x86 on day 1 of announcing a move to a new architecture as they effectively declare it a 'legacy' product.
But why not just jump and let momentum carry x86 like before? The problem with Itanium was largely that the ISA itself sucked to work with and SW/tools were not ready for prime time when 3p SW/HW vendors like Nvidia were expected to have ported to it.
It doesn't seem like ARM and maybe RISC-V will have the same issues, at leatin terms of magnitude so I don't really see why it matters.
I think long term they risk ending up like Canon/Nikon in the DSLR market when Sony came along with the new fangled mirrorless technology - sometimes you gotta disrupt yourself and skate to where the pick is going.
Largely agree. I'd be astonished of they don't have high performance RISC-V designs under development.
Problem is that the endpoint is much less attractive (for them) than where they are now and the transition will be very, very messy. At a time when the business is under strain for other reasons it's a risky move.
Should have done it a few years ago - when they had process lead - but hindsight is a wonderful thing!
Itanium was absolutely a plan to take out the competitors in the unix- and minicomputer market, where margins were much, much higher than in the generic x86 market. That worked. SGI, Digital, HP, Compaq/Tandem, they all fell.
It was not necessarily the plan to abandon the architecture, but once it was won, it also wasn't terribly important to keep going. Much like most corporate takeovers to this day.
Intel would have been happy to keep the market segmented for a few more years, but what happened instead was that the market vacuum was filled by Linux and x86 instead. That would likely have happened sooner or later anyway, but there you go.
It was a poor architecture though and if not by AMD64 it would have been killed by something else more in line with traditionnal high perf superscalar. Maybe even just Arm.
Even Microsoft directly shipped a PowerPC system running a modified NT kernel in the Xbox 360.
If Itanium continued to implode with no other alternatives, PowerPC would have been the most likely to pick up the slack. The main reason why it more or less failed was from a lack of volume to pay for leading edge R&D for the process side. Without AMD64, Intel's Itanium obsession combined with the mid aughts dennard scaling wall catching everyone with their pants down would have given a nice bit of breathing room for PowerPC to exceed x86-32.
They killed it at about the time they started working on AMD64 internally with AMD. Dave Cutler himself gave feedback on the pre silicon design; it was basically co designed with Microsoft. They kept PowerPC in public products until they had another way out. And to this day PowerPC support still exists internally in the NT kernel.
They also literally were shipping an NT derived kernel for Xbox 360 into the 2010s.
Between 1997 and the release of XBox in 2001 there was enough years of code changes (two major NT based releases), also XBox NT kernel was basically that, a stripped down kernel without any relation to Windows 2000 userspace.
And notice I said 360; they reimported the PowerPC support from mainline NT in 2005. And to this day they still have PowerPC support internally in mainline NT.
And that small bit doesn't address the core of what I'm saying, that PowerPC support would have seen even more support if the two options were that and Itanium.
Today not 'everyone' is using x86 - by a long margin - so it's a bit of a stretch to say that in a hypothetical alternative history an architecture that failed in the market would be utterly dominant.
If you exclude everything that does not go into your direction and make the hypothesis that a poor architecture would have risen and then would not have been replaced, you conclude that "everybody" would use it?
No people would just use 32 bit x86 and continue with that for many more years and move to SPARC/PowerPC for the few cases where you really need 64 bit.
People not just gone use really bad processors because they have no other options.
This was right in the time period of Windows Everywhere. Windows on MIPS, Alpha and so on. And for server workloads just using going to Unix is totally fine.
People would rather run server workloads on Unix rather then using windows with shitty expensive processors.
People that are unwilling to move to Unix very likely just stick around on 32bit instead.
That version of Windows died with NT 4.0, several years before Itanium was a product.
We were running Windows 2000 in production, alongside Aix, HP-UX and Solaris workloads across all our customers back in 1999 - 2003, before we got hit in the first .com startup crysis.
Yes, ISA's matter, to a point. And yes, ARM64 and RISC-V are much closer to 'best practice' ISA design than x86 with all its legacy baggage. But enough better to make AMD&Intel throw away the x86 market and their position in that as explained in the parent comment? No effing way.